In multiphase power supply systems, a load is divided into several regions. A multiphase power controller in such systems is divided into a number of phases that are assigned to a corresponding number of regions of the load. Normally there is a one to one mapping between the number of phases and the regions of the load.
The multiphase power controller generates multiple PWM (pulse width modulation) outputs that drive multiple power stages. The multiphase power controller operates by sharing equal currents among all the phases. A power stage includes an inductor and a switching circuitry having a driver. Therefore, the current passing through the inductor in the power stages is shared equally, then added and delivered to the load. An ‘n’ phase power controller provides ‘n’ PWM outputs to ‘n’ power stages. The PWM outputs are generated from the controller in response to the inductor currents and output voltage of the power stages in a closed loop.
In multiphase controllers, the load current is shared among the multiple phases even when the load current is low. Multiple power stages and other internal circuits continue to switch in such low load currents generating multiple PWM outputs. In other words, the PWM outputs are active for a 0 load current to a MAX load current. The PWM outputs being active at lower load conditions contributes to power consumption, conduction losses and switching losses affecting the efficiency of the multiphase power supply system.